Lubricants



United States Patent 3,304,257 LUBRICANTS Wilhelm Schauzer, Munich,Germany, assignor to Molykote Produktions G.m.b.H., Munich, Germany NoDrawing. Filed July 19, 1965, Ser. No. 473,190 Claims priority,application Germany, July 22, 1964,

6 Claims. (Cl. 252-25) This invention relates to novel lubricants whichare particularly useful for cold-drawing and otherwise cold shapingmetals without splintering the metal.

In deep drawing and shaping metals and similar metal processing whereinsignificant frictional forces are encountered, the formation ofsplinters and other difficulties necessitates the use of lubricants. Thetools employed for drawing, shaping and forming metals are of greatvalue and must be conserved else their use is economically unfeasible.Further, the development of hot spots and localized overheating,formation of channels, scratches, gouges and pits on the surface of themetal article being processed is wholly undesirable. To avoid damage tothe tools employed and to the metal article being processed it iscustomary to employ a variety of lubricants. The lubricants for metaldrawing can be in the form of fluids, pastes, fatty materials as well assolid lubricants. The important characteristic of the lubricants forthis use is the reduction of the heating eifect caused by working themetal and this cooling can be accomplished by dissipating the heat at arapid rate as well as by actual reduction of friction, etc.

Heretofone, soaps such as alkali metal and alkaline earth metal salts ofhigher fatty acids, 'boric acid and derivatives of boric acid in theform of solids, in aqueous systems, in oily systems and in paste-likepreparations have been used as lubricants in the deep drawing of metals.Similarly employed have been inorganic solid lubricants with layerlattice structure. The use of phosphate compounds in such lubricants isalso known.

The primary object of this invention is to introduce a novel lubricantfor use in deep drawing, forming and machining of metals. Other objectsand advantages of this invention are detailed in or will be apparentfrom this disclosure and appended claims.

It has been unexpectedly found and this invention teaches that aluminumsalts of phosphorous-oxygen acids are eminently useful as lubricants forcold processing of metals.

The aluminum salts employed herein are formed from phosphorous-oxygenacids wherein the phosphorous is electropositive and is triorpentavalent. Examples of such acids are ortho, pyroand meta-phosphoricacids, ortho-, pyroand meta-phosphorous acids and the known oligomericand polymeric phosphorous-oxygen derivatives.

The aluminum salts of the phosphorous-oxygen acids can be employed in awide variety of forms. They can be employed as dry lubricants alone orin mixture with other lubricants. When these salts are added to otherlubricants, it is preferred that they be present to the extent of atleast 1% by weight, based on the mixture. Thus, they can be mixed withextenders and/or other lubricating solid organic or inorganic carriers.For example, the aluminum salt can be mixed withpolytetrafluoroethylene, polychlorotrifluoroethylene powders or withmetal sulfide "ice lubricants and the mixture can be incorporated orworked into organic plastics. Furthermore, the aluminum salts can beadmixed with mineral oils and known synthetic lubricating oils as wellas petroleum products to produce a variety of lubricants varying fromfluids to pastes. Incorporation of the aluminum salt in a wax-likelubricant provides lubricating sticks which can be readily employed in awide variety of applications. Lubricating greases and viscous naturaland synthetic carriers can also be admixed with the aluminum salt toproduce a grease or paste-like mass and the carrier may itself be alubricant.

The aluminum salt can be uniformly distributed throughout the carrier oradmixed ingredients in any manner desired. Generally the evendistribution is more easily accomplished in the presence ofviscosity-modifying materials or materials capable of effectingthixotropy.

The aluminum salts can, of course, be added to fluid carriers which canbe inorganic or organic, natural or synthetic but should 'be ofsufliciently low viscosity to accomm-odate the aluminum salt withoutforming a paste of viscous fluid. Such fluid carriers as water,alcohols, mineral oils, polyester fluids, polyphenyl ether and the likecan be employed. The fluid carrier can be nonlubricating or it can be alubricant which is relatively inferior, superior or equal to thealuminum salt. It is generally preferred to employ a lubricating fluidas a carrier if the ultimate product is to be in fluid form. The fluidsshould contain dispersion stabilizers to insure a uniform product ofuniform characteristics.

Basically, the aluminum phosphorous-oxygen compounds used as lubricantsin the present invention can be used together with other lubricatingmaterials and other compounds common in the lubricating art, as forexample, emulsifiers to make articles easier to clean. The corrosioninhibiting properties of the aluminum phosphates can be augmented by theaddition of other corrosion inhibitors.

The following examples serve to clarify the discovery. They also serveto illustrate the exaellent results obtained by observing the teachingsof the present discovery.

EXAMPLE 1 Aluminum phosphate in. water The friction scar area wasmeasured on the Reichert friction and wear tester under 30 kg. load and100 m. sliding contact. Water was employed as the lubricant and theresulting scar area had an average value (three measurements) of 32.6sq. mm. A mixture of 5 parts by weight aluminum phosphate and 95 partsby weight water was employed as the lubricant and the test was repeated.The friction scar area had an average value (three measurements) of 7.3sq. mm.

EXAMPLE 2 Aluminum phosphate in emulsions Following the procedure ofExample 1, a mixture of parts by weight mineral oil, 9 parts water and 1part emulsifying agent tested as a lubricant on the Reichert frictionand wear tester gave an average friction scar area of 37.2 sq. mm. Amixture of par-ts of the mineral oil, Water, emulsifying agent mixtureand 5 parts by weight of aluminum phosphate, similarly tested gave anaverage friction scar area of 22.9 sq. mm.

3 EXAMPLE 3 Aluminum phosphate in greases A lithium soap grease wastested on the Almen-Wieland lubricant testing machine and on the Shellfour-ball extreme pressure lubricant testing machine. A four percent byweight loading of aluminum phosphate was then added to the lithium soapgrease and the tests were repeated. The results are tabulated below:

Aluminum phosphate in pastes A mineral oil was tested on theAlmen-Wieland machine and thereafter 30 parts by Weight aluminumphosphate was mixed with 70 parts by weight of the mineral oil and themixture was also tested on the Almen-Wieland machine. The mineral oilhad a loading capacity of 200 kg. and the mineral ioil-aluminum saltmixture had a loading capacity of 800 kg.

EXAMPLE 5 Results equivalent to' those set forth above were accomplishedwhen aluminum salts of metaphosphoric acid, phosphorous acid,pyro'phosphoric acid, pyrophosphorous acid and metaphosphorous acid weresubstituted for the aluminum phosphate (eg. in Example 4).

That which is claimed is:

'1. A lubricating composition containing at least 1 percent by Weight ofan aluminum salt of an acid selected from the group consisting ofphosphoric and phosphorous acids.

2. A fluid lubricant containing 21()% by weight of an aluminumphosphate.

3. A lubricating oil containing 24% by weight of an aluminum salt of aphosphorous-oxygen acid selected from the group consisting of phosphoricand phosphorous acids.

4. A lubricating grease containing 15-40% by weight of an aluminum saltof a phosphorous-oxygen acid selected from the group consisting ofphosphoric and phos phorous acids.

'5. A novel lubricant particularly useful for splinterfree cold met-a1processing characterized by the presence of at least 1 percent by weightof an aluminum phosphate in the lubricant.

6. in a lubricant, the improvement comprising incorporating therein atleast 1 percent by weight of an aluminum salt of an acid selected fromthe group consisting of phosphoric and phosphorous acids.

References Cited by the Examiner UNITED STATES PATENTS 1,932,454 10/1933Franks 252-25 X 2,588,234 3/1952 Henricks 25225 X 3,186,945 6/1965 Graueet al. 252- 25 DANIEL E. WYMAN, Primary Examiner.

C. F. DEES, Assistant Examiner.

1. A LUBRICATING COMPOSITION CONTAINING AT LEAST 1 PERCENT BY WEIGHT OFAN ALUMINUM SALT OF AN ACID SELECTED FROM THE GROUP CONSISTING OFPHOSPHORIC AND PHOSPHOROUS ACIDS.